Side seam sealing mechanism for bag making machines



T. E. PIAZZE Oct. 23, 1962 SIDE SEAM SEALING MECHANISM FOR BAG MAKING MACHINES 4 Sheets-Sheet 1 Filed Jan. 26, 1959 IN V EN TOR.

I BY

Oct. 23, 1962 T. E. PrAzzE 3,059,547

SIDE SEAM SEALING MECHANISM FOR BAG MAKING MACHINES Filed Jan. 26, 1959 4 Sheets-Sheet 2 JUNK/all! l f zywgzvron I f\ 74:17pm W T. E. PIAZ'ZE Oct. 23, 1962 SIDE SEAM SEALING MECHANISM FOR BAG MAKING MACHINES 4 Sheets-Sheet 3 INVENTOR.

65% MMvWW Filed Jan. 26, 1959 1] I'll lull ll-lll'l IL c NE T. E. PIAZZE Oct. 23, 1962 SIDE SEAM SEALING MECHANISM FOR BAG MAKING MACHINES Filed Jan. 26, 1959 4 Sheets-Sheet 4 IN V EN TOR.

United States Patent Q 3,659,547 SIDE SEAM SEALING MECHANISM FOR BAG MAKING MACHINES Thomas E. Piazze, Mount Vernon, Ohio, assignor to Continental Can Company, Inc, New York, N.Y., a corporation of New York Filed Jan. 26, 1959, Ser. No. 788,820 8 Claims. (Cl. 93-12) This invention relates to packaging and is particularly concerned with improvements in a machine for automatically fabricating from a web of pliable sheet material open ended bag type containers which are adapted to receive goods to be packaged.

The invention is especially adapted to be embodied in apparatus which constitutes an improvement in the machine disclosed in applicants copending application Serial No. 657,853, filed May 8, 1957, now Patent No. 2,942,- 529, dated June 28, 1960, which machine is of the type wherein a continuous web of heat sealable bag forming film material is divided into bag forming sections or sheets, successive sheets are fed to a series of forming mandrels carried on a continuously traveling conveyor which mandrels engage the sheets and carry them past associated folders which fold the sheets into bag forming relation around the mandrels, after which they are engaged by heat sealers which form longitudinal side seams in overlapped marginal portions of thesheets.

It is a general object of the invention to provide in a bag making machine of the type described an improved mechanism for engaging heat sealing irons with the mandrels to form longitudinal side seams in overlapped marginal portions of the bag material which is carried on the mandrels.

It is a more specific object of the invention to provide in a bag making machine of the type which has a series of mandrels carried on a continuously traveling conveyor, a sheet feeding mechanism which delivers to each of the mandrels a bag forming sheet, and a folding tunnel in which the sheets are shaped around the mandrels, the improvement which comprises a cross shaft mounted above the path of the mandrels adjacent the end of the folding tunnel, a pair of bracket members mounted in threaded relation thereon, which bracket members support in depending relation therefrom sealing irons adapted to be engaged with the mandrels to form longitudinal side seams in overlapped marginal portions of the sheets thereon and mechanism for rotating the cross shaft to move the sealing irons into and out of engagement with the mandrels.

These and other objects and advantages of the invention will be apparent from a consideration of the apparatus which is shown by way of illustration in the accompanying drawings wherein:

FIGURE 1 is a side elevation of a portion of a bag forming machine having incorporated therein the principal features of the invention, the view being partly diagrammatic;

FIGURE 2 is a plan view of the portion of the machine shown in FIGURE 1 with parts thereof broken away or omitted;

FIGURE 3 is a side elevation to an enlarged scale of a portion of the mechanism shown in FIGURE 1;

FIGURE 4 is a side elevation showing a portion of the mechanism of FIGURE 3 with the members in a different position;

FIGURE 5 is a side elevation to an enlarged scale of a portion of the mechanism shown in FIGURE 2, the view being taken on the far side of the machine and having portions broken away;

FIGURE 6 is a cross section taken on the line 6-6' of FIGURE 2 to an enlarged scale and with portions broken away;

FIGURE 7 is a section taken on the line 77 of FIG- URE 6;

' FIGURE 8 is a fragmentary plan View taken on the line 8-8 of FIGURE 6; and

FIGURES 9 and 10 are schematic views illustrating successive operations in the manufacture of the bags.

The illustrated machine in which the invention is embodied is adapted to fabricate bags which are formed from either single or multi-ply material drawn from a single supply roll or a plurality of rolls. Two webs are fed or a single web is split longitudinally and the two portions fed in a vertical path through an adhesive applying mechanism and an intermittently operated transverse severing device which is timed to sever from the traveling web portions individual sheets 10 (FIGURES 1, 2, 9 and 10). The sheets 10 are guided into the paths of a plurality of forming mandrels 11 carried in double line arrangement on endless chains which operate as a single conveyor 12. The sheet material which forms the walls of the bag is preferably a flexible, transparent, heat scalable film material, such as cellophane, mylar, pliofilm, polyethylene or similar plastic. In feeding the webs to the mandrels an adhesive, of the quick drying heat acti vatable type, is applied in laterally spaced stripes or lines 13 to the marginal portions of the sheets 10 so that the marginal portions may be overlapped and the adhesive activated to form the side seams.

The two lines of forming mandrels 11 (FIGURES 1, 2, 9 and 10) are arranged in spaced relation and in longitudinal alignment on the supporting conveyor 12 for intermittent advancing movement in parallel horizontal paths. Each successive mandrel 11 (FIGURES 9 and 10) picks up a bag forming sheet 10 as the latter is fed into its path, the mandrel engaging the inside surface of the sheet 10 intermediate the ends thereof. The mandrels 11 advance through folding mechanism 14 which operates to fold each sheet 10 around a mandrel 11 so that the marginal side edge portions which carry the lines of adhesive 13 are overlapped on the side faces of the mandrel 11. From the folding mechanism 14 the respective mandrels 11 advance to a heat sealing mechanism 15 which comprises a double line of heat sealing irons 16, the latter being arranged in paired relation on opposite sides of the path of each line of mandrels 11. The heat sealing members 16 are reciprocated to press against the opposite side faces of the mandrels 11 so as to form a T-shaped seam 17 in each of the overlapped marginal edge portions of the sheet which constitute the side walls of the completed bag 18. As the mandrels 11 advance beyond the heat sealing members 16 the bags 18 are stripped from the mandrels 11 and delivered from the machine.

The conveyor 12 and associated bag forming mechanisms are supported on an upright frame, portions of which are indicated at 20 (FIGURES 1, 2 and 6). The conveyor 12 comprises laterally spaced pairs of endless chains 21 (FIGURE 2) which are supported at opposite ends on pairs of forward and rearward sprocket members 22 and 23, which sprocket members are mounted on cross shafts 24 and 25, with the cross shafts being journaled in upstanding side plate members of the supporting frame 20.

The bag forming mandrels 11 are each secured betweena pair of chains 21 by a bracket member 26 which is secured on a pair of transverse supporting rods 27 so that the mandrels extend forwardly of their attachment to the chains and move in a generally horizontal plane when they advance along the top run of the conveyor, the two lines of the mandrels traveling in the same horizontal plane and in parallel paths which are spaced transversely of the machine.

The sprocket supporting shaft 24 at the forward end of the conveyor 12 is connected by a gear drive, indicated at 28, to the main drive shaft of the machine which is indicated at 30, and which is connectedwith the output shaft of a suitable motor (not shown) or other source of power. The driving connection between the main drive shaft 30 and the conveyor shaft 24 includes an intermittently operationg Geneva mechanism for providing intermittent movement of the conveyor 12.

The mandrels 11 are supported and guided along the upper run of the conveyor 12 on transversely extending table foiming plate members 31 which are slotted longitudinally at 32 to provide a passage or guideway for the brackets 26 connecting the mandrels 11 with the chains 21 of the conveyor 12. The plate members 31 are also transversely slotted at 33 to accommodate the leading ends of the bag forming sheets 10. Each successive mandrel 11 engages the leading end thereof with a bag forming sheet 10 as the mandrel advances onto the supporting plate 31 and the sheet 10 is fed into the path of the mandrel. The mandrel carries the sheet 10 through a folding chute 14 which includes fold forming plates arranged to cooperate with the mandrels in wrapping the sheet 16 about the mandrel with the side marginal portions of the sheet in overlapped relation for forming a side seam. Details of the mechanism for guiding the mandrel and for folding the sheet about the mandrel which are not shown and described herewith are disclosed in applicants copending application Serial No. 657,853.

As the mandrels 11 are advanced by the conveyor 12 beyond the folding chute 14, they pass through a heat sealing mechanism 15 which activates the adhesive in the lines 13 between the folded marginal portions of the sheet 10 so as to form a T-shapcd seal 17. The heat sealing mechanism 15 is mounted on a subframe 40 (FIGURE 2) which comprises upright side frame plates 41 and 41' extending above and attached to longitudinal side frame plates of the main supporting frame 20, adjacent the end of the upper run of the conveyor 12. The heat sealing mechanism 15 comprises two longitudinally spaced, transversely extending lines of heat sealing iron members 16 which are supported on transversely extending, longitudinally spaced shafts 42 and 42'. The shafts 42 and 42 are journaled at theirends in suitable hearings in the upright side frame plates 41 and 41.

The heat sealing members or bars 16 are identical in construction and each is provided with a suitable electrical resistance element for heating the same. The two lines of sealing bars 16 are carried in an identical manner on the cross shafts 42 and 42. Each sealing bar or iron 16 (FIGURES and 6) is attached to the lower end of a supporting bracket 43 which depends from the cross shaft 42 or 42'. The brackets 43 are arranged in pairs and each sealing iron 16 is attached to its supporting bracket 43 by a pair of stud bolts 44. The bolts 44 extend through vertical slots 45 in the two legs of the bracket 43 so as to permit vertical adjustment of the sealing iron 16 on the bracket 43. The supporting brackets 43 each have a hub forming portion 46 which fits over the hub portion 47 of a flanged bushing 48 with one end thereof abutting against the peripheral flange 49 on the bushing 48 and connected thereto by stud bolts 50 extending through peripherally spaced slots 51 which permit adjustment between the bracket 43' and the bushing 48. The hub portion 47 of each bushing 48 is internally threaded and the shafts 42 and 42 are provided with left and right hand threaded portions 52 and 52' for cooperation therewith. Each of the brackets 43 has an upstanding flange portion 54 which carries a pair of guide rollers 55, with the latter mounted on vertically extending spaced shaft forming studs 56 so as to engage on opposite sides of a cross guide bar 57. The guide bars 57 and 57' (FIGURE 3) for the two lines of sealing members are secured at the opposite ends to the upper edges of the upstanding bracket members 58 and 58' which form part of the bearing sturctures for the cross 4 shafts 42 and 42'. The guide rollers 55 and the guide bars 57 and 57' insure cross travel of the brackets 43 without tilting motion around the supporting and operating shafts 42 and 42'.

The shafts 42 and 42' are extended at one end through the vertical frame plate 41 and carry on their extended ends pinions 60 and 60' which engage with a horizontally sliding rack 61. The rack 61 is mounted in a carriage forming upwardly opening channel-shaped bar 62. The rack carriage 62 is supported on a pair of longitudinally spaced bearing rollers 63 and 63' which are arranged on shaft forming studs 64 and 64' on the side frame plate 41. In addition to the pinion and rack connection, the two shafts 42 and 42' are also connected by a chain 65 mounted on sprockets 66 and 66' secured on the respective shafts 42 and 42 so as to insure simultaneous rotation of the two shafts with uniform movement thereof. The shafts 42 and 42' are rotated or oscillated by reciprocation of the rack 61 to carry the sealing irons 16 toward and from the mandrels 11.

The movement of the rack 61 is controlled by a cam operated mechanism (FIGURES l and 3) connected to one end thereof. A link bar 70 has one end thereof pivotally connected at 71 to the end of the rack carriage 62 and is provided at its other endwith a handle forming portion 72. The link bar 70 has an L-shaped slot 73 intermediate its ends which receives a pin 74 projecting laterally of the free end of the vertically extending arm 75 of a bell crank member 76 which is pivoted at 77 on the side frame 2b of the machine and has a short horizontally extending arm '73 carrying a cam roller 80 which is received in the cam track 81 of the operating cam 82. The cam 82 is mounted on the cross shaft 83 which carries a gear 84 connected in driven relation with a pinion 35 on the cross shaft 86, the latter being connected with the main power shaft 30. The pin 74 on the vertical arm 75 of the bell crank normally rides in the short vertically extending leg 87 of the slot 73 and reciprocates the rack carriage 62.

The link bar '70 is adapted to be swung on its pivot 71 to an elevated position for preventing reciprocation of the rack carriage 62. Raising of the link \bar 70 throws the pin 74 into the long horizontal portion 88 of the slot 73 which prevents reciprocation of the rack carriage 62. The link bar 70 is lifted by movement of the hanger bar 90 (FlGURES 3 and 4) which is pivotally suspended at 91 on the free end of a crank arm 92, the latter being secured on a cross bar or shaft 93 journaled in the side frame plates 41 and 41'. The crank arm 92 is connected by a link 94 with a crank arm 95 se cured on an upper shaft 97 extending between upstand ing bearing brackets 98 and 98 on the top edge of the side plates 41 and 41'. The hanger 90 has a bifurcated lower end which straddles the link bar 70 and which is provided with a cross pin 100. The cross pin 100 is adapted to engage with the bottom edge of the link 70 when the shaft 97 is rotated to lift the hanger 90 a pre determined distance. A latch mechanism is provided at the opposite side of the machine to hold the shafts 93 and 97 in either of the two positions which are shown in FIGURES 3 and 4. The latch mechanism comprises an arm 101 (FIGURE 5) secured on the shaft 97 and connected by pivot 102 with the upper end of a bifurcated member 103 having its depending legs 104 and 104' straddling a block 105 pivotally mounted on the shaft 93. A compression spring 106 extends between the block 105 and a flange or tongue member 107 extending from the face of the member 103 and urges the memher 103 and block 105 away from each other with the force of the spring exerted on a line connecting the axis of pin 102 and shaft 93. A handle 108 is provided on the upper shaft 97 so that the shaft 97 may be rotated to swing the pin 102 forward and backward between opposite sides of a vertical plane extending through the axes of the shafts 93 and 97. Stop pins 110 and 110' are provided to limit the rotational movement of the shaft and 5 hold the latch mechanism in operative position in either one or the other of its two positions.

A pair of guard plates 111 and 111' (FIGURE 8) are secured on the frame at the end of the folding chute 33 and below the shaft 42 to hold the overlapped side seam material in position until the first sealing contact with the sealing irons 16.

The one cross shaft 42 may be provided with a hand Wheel 112 to facilitate adjustment of the stroke and timing of the sealing irons 16 While the machine is idle or while the rack carriage 62 is not reciprocating.

-In the operation of the mechanism, the sealing irons 16 are adjusted on the brackets 43 for contact with the mandrels 11 at the proper elevation. The brackets 43 are then adjusted by means of the bolt 50 and slot 51 connections with the mounting sleeves 48 to provide the proper reciprocating movement for obtaining the desired pressure of the irons 16 against the mandrels 11 when the shafts 42 and 42 are rotated. The rotational movement of the shafts 42 and 42' is adjusted by proper location or adjustment of the pinions 60, 60' and the sporckets 66, 66' on the shafts to provide simultaneous movement of all the irons 16. The reciprocating movement of the operating rack 61 is timed by adjustment of the cam 82 on its shaft 83 so that the sealing irons 16 engage the mandrels 11 while the intermittently operating conveyor 12 is at a standstill between advancing movements. The sealing mechanism may be thrown out of operation at any time by merely swinging the link 70 to the inoperative or up position so that the pin 74 rides in the slot portion 88. The link 70 may, of course, be latched in either operative or non-operative position.

While particular materials and specific details of construction have been referred to in describing the illustrated form of the apparatus, it will be understood that other materials and different structural details may be resorted to Within the spirit of the invention.

I claim: I

1. In a machine for forming flexible containers, which machine has a traveling conveyor mounted on a supporting frame with bag forming mandrels mounted in longitudinally spaced relation thereon so as to move against sheets of bag forming material delivered into the path traversed by the mandrels and folders adjacent the path of the mandrels for positioning the sheets around the mandrels with marginal portions overlapping in seam forming relation and with lines of heat activata-ble adhesive between the folded over marginal portions: a heat sealing mechanism comprising a cross shaft exten ing transversely of the conveyor which cross shaft has axially spaced right and left hand threaded portions, brackets having threaded bores mounted on the threaded portions of said cross shaft, each of said brackets carrying a heat sealing iron, said brackets being spaced to position the sealing irons on opposite sides of the path of the mandrels, and means including a driven cam for intermittently rotating said cross shaft to move said brackets laterally of the path of travel of the conveyor mandrels and toward and from each other at predetermined intervals so as to engage the sealing irons against the sides of successive mandrels which are advanced by the conveyor for periods sufficient to activate the adhesive and form the seams in the overlapping portions of the sheets.

2. In a machine for forming flexible containers, which machine has a traveling conveyor mounted on a supporting frame with bag forming mandrels mounted in longitudinally spaced relation thereon so as to move against sheets of bag forming material delivered into the path traversed by the mandrels and folders for positioning the sheets around the mandrels with marginal portions overlapping in seam forming relation and with a heat activatable adhesive between the folded over marginal portions: a heat sealing mechanism comprising a 6 pair of spaced cross shafts extending transversely of the conveyor which cross shafts have right and left hand threaded portions, brackets having threaded bores mounted on the threaded portions of said cross shafts, each of said brackets carrying a heat sealing iron, said brackets being arranged in pairs with the sealing irons of each pair positioned in spaced apart relation on opposite sides of the path of the mandrels, and means for intermittently rotating said cross shafts in timed relation to the advancing movement of the conveyor whereby to move the brackets of each pair thereof toward each other so as to engage the sealing irons against the sides of the mandrels which are advanced by the conveyor, said rotating means comprising a reciprocating rack and pinions on said shafts engaging with said rack.

3. In a machine for forming flexible containers, wherein a series of bag forming mandrels are mounted on a supporting conveyor and adapted to be moved against sheets of bag forming material delivered into the path traversed by the mandrels and through a folding tunnel for positioning the sheets around the mandrels with marginal portions overlapping in seam forming relation and with a heat activatable material between the overlapped marginal portions: a heat sealing mechanism comprising a pair of cross shafts spaced in the direction of travel of the mandrels and extending transversely of the conveyor which cross shafts each have axially spaced right and left hand threaded portions, brackets having threaded bores mounted on the threaded portions of said cross shafts, each of said brackets carrying a heat sealing iron, said brackets being arranged in pairs with the sealing irons of each pair positioned in spaced relation and on opposite sides of the path of the mandrels, and means for rotating said cross shafts in timed relation to the advancing movement of the mandrels whereby to move the brackets of each pair thereof toward and from each other so as to engage the sealing irons against the sides of the mandrels, said rotating means comprising a slidably mounted rack, pinions on said shafts engaging with said rack and means for intermittently sliding said rack back and forth on its mounting.

4. In a machine as recited in claim 3, and said rack sliding means comprising a rotatable cam, a bell crank pivotally mounted for oscillation by said cam, a link having a pivotal connection with said rack, and a pin and slot connection between said link and said bell crank.

5. In a machine for forming bags from flexible sheet material which machine has a bag forming mandrel mounted on a movable support and associated mechanism for forming a sheet of the material around the mandrel with portions overlapping in seam forming relation and with a heat activatable material between the seam forming portions: a heat sealing mechanism comprising a rotatably mounted cross shaft extending transversely of the path of the movable support which cross shaft has axially spaced right and left hand threaded portions, a

- pair of brackets having threaded bores mounted in spaced relation on the threaded portions of said cross shaft, each of said brackets carrying a heat sealing iron, said brackets being spaced so that the sealing irons extend therefrom on opposite sides of the path of the movable support, said cross shaft having a pinion thereon, a rack mounted for reciprocating movement adjacent the pinion and cooperating with the pinion to oscillate said shaft thereby to move the brackets toward and from each other on the shaft and intermittently engage the sealing irons against the mandrel, a guide ba-r mounted in fixed parallel relation with said cross shaft, and means forming a sliding connection between each bracket and said guide bar whereby to prevent rotation of the bracket on said cross shaft while permitting movement thereof in the direction of the axis of rotation of said cross shaft.

6. In a machine for forming flexible containers, said machine having a traveling conveyor mounted on a supporting frame with bag forming mandrels carried on the conveyor and means for foldingaround the mandrels sheets of bag forming material delivered into the path traversed by the mandrels which sheets have overlapping seam forming portions with heat sealing characteristics, a heat sealing mechanism comprising a cross shaft extending transversely of the conveyor, brackets mounted for reciprocating movement on said cross shafts, means connecting the brackets to the shaft so that they move along the axis of the shaft when the shaft is rotated, a heat sealing iron on each of said brackets, said brackets being spaced so that the sealing irons are positioned on opposite sides of the path of the mandrels, a transversely extending fixed support member, interengaging means on said brackets and said fixed support member for guiding said brackets in their reciprocating movement and continuously operating power means having an intermittently operating connection with said cross shaft so as to reciprocate said brackets on the shaft and engage the sealing irons against the sides of successive mandrels as they are advanced by said conveyor for a sufiicient interval of time to seal the overlapping seam forming portions of the bag forming material and thereafter to withdraw the sealing irons from engagement with the mandrels.

7. In a machine for forming flexible containers, said machine having a traveling conveyor mounted on a Supporting frame with bag forming mandrels on the conveyor and means for folding around the mandrels sheets of bag forming material delivered into the path traversed by the mandrels which sheets have overlapping seam forming portions with heat activatable adhesive thereon, a heat sealing mechanism comprising a rotatably mounted cross shaft extending transversely of the conveyor and having axially spaced threaded portions, bracket sleeves having threaded bores mounted on the threaded port-ions of said cross shafts, brackets mounted on'said sleeves for totational movement, each of said brackets carrying a heat sealing iron, said brackets and said sleeves being spaced on said shaft so as to position the sealing irons on opposite sides of the path of the mandrels, transversely extending, fixed guide means, cooperating movable guide means on the brackets for guiding said brackets in a transverse path and intermittently operating power means for oscillating said cross shaft in timed relation to the travel'of the conveyor thereby moving said brackets toward and from the mandrels and intermittently engaging the sealing irons against successive mandrels as they are advanced by said conveyor so as to activate the adhesive on the seam forming portions of the bag material.

8. In a machine for forming bags from flexible sheet material, said machine having a bag forming mandrel mounted on a movable support and associated mechanism for forming a sheet of material around the mandrel with portions overlapping in seam forming relation and with heat activatable material between the seam forming portions, a heat sealing mechanism comprising a rotatably mounted cross shaft extending transversely of the path of the movable support which cross shaft has axially spaced right and left hand threaded portions, a pair of brackets having threaded bores mounted in spaced relation on the threaded portions of said cross shaft, each of said brackets carrying a heat sealing iron, said brackets being spaced so that the sealing irons extend therefrom on opposite sides of the path of the movable support, intermittently operating power driven means connected to said shaft for oscillating said shaft at regular intervals thereby to move the brackets toward and from each other on the shaft and intermittently engage the sealing irons against the mandrel, means forming a track mounted in fixed parallel relation with said cross shaft, and means on each bracket engaging in sliding relation in said track whereby to prevent rotation of the bracket on said cross shaft While permitting movement thereof in the direction of the axis of rotation of said cross shaft.

References fired in the file of this patent UNITED STATES PATENTS 

